President Benigno Aquino has unveiled new arms purchases worth at least 30 billion pesos (US$671 million) to modernise the Philippine military amid recent skirmishes with China in the South China Sea.

In a speech yesterday before graduating cadets of the Philippine Military Academy, Aquino announced that the Armed Forces of the Philippines (AFP) would receive 63,000 new firearms to replace the Vietnam War-era M16 and M14 rifles that most of its soldiers are still using.

The Philippine military also has in its arsenal newer versions of the M16, the M4 carbine and Steyr Aug assault rifle, but these are mostly reserved for special forces units.

"Look at the rifles our soldiers use. Most of them were used during the Vietnam War. The good news: we expect 63,000 new rifles for our Armed Forces in the coming months," said Aquino.

He said the country is also purchasing 12 FA-50 fighter jets from South Korea, eight combat utility helicopters and two anti-submarine helicopters.

The 12 FA-50s, light attack aircraft costing 18.9 billion pesos, should be in service next year.

These purchases are part of the AFP's 15-year modernisation programme that started in 2012.

The Philippines has so far spent 41.2 billion pesos on 36 modernisation projects since 2012, and it has earmarked another 40 billion pesos till 2017.

The modernisation programme is being spurred largely by increasing tension between Manila and Beijing in recent years over their territorial disputes in the resource-rich South China Sea, which has seen increasing skirmishes between the two sides.

The Philippine Navy has acquired two refurbished United States Coast Guard cutters, worth 18 billion pesos, which now form its vanguard.

Three new helicopters for the air force were also commissioned last December.

Manila recently opened tenders for two more frigates worth 18 billion pesos to reinforce the two cutters now patrolling the South China Sea.

It is also negotiating for five patrol boats from France and multi-role vessels from South Korea, and is known to be in the market for a submarine.

The Philippine Army, meanwhile, is awaiting delivery of 2.8 billion pesos worth of troop carriers, armoured vehicles and field ambulances.

Last December, China's Coast Guard used water cannon to drive away Filipino fishing boats close to Scarborough Shoal, the site of a stand-off between the Philippines and China in 2012.

On March 9 this year, two Philippine vessels trying to resupply a group of marines at Second Thomas Shoal were driven away by Chinese cutters.

Apart from modernising the military, Manila is also reinforcing its borders through a defence pact that will allow the US to station more troops on Philippine shores for a longer period of time.

In line with the pact, the Philippines has been upgrading a network of bases and radars to better track Chinese movements in the South China Sea.